Professor Scheraga[unreadable]s group has made a mutant of Ribonuclease A which contains a single tryptophan residue (Trp92). This mutant has known fluorescent properties which can probe conformational changes associated with thermal unfolding. Unfolding will be initiated via a laser induced temperature jump and fluorescence will be monitored on sub ms (ps to ?s) timescales. These studies are now underway.